1. Field of the Invention
The present invention relates generally to a Software Defined Network (SDN)-based network sharing method and apparatus for supporting multiple operators, and more particularly, to an SDN-based network sharing method and apparatus for supporting multiple operators to operate a network equipment shared by multiple operators in an easy and optimized way.
2. Description of the Related Art
The recent network has been operated in a combined complex network structure of an existing wired network and a wireless network. Due to the increasing number of users that use the next-generation mobile communication system, such as Long Term Evolution (LTE), the network traffic has increased exponentially.
In this complex network structure, due to the rapid increase in the number of users using the next-generation mobile communication such as LTE, an operator desiring to newly build a network needs to share resources of the network equipments operated by the mobile network operators. Therefore, there is a need for a technique in which multiple operators operate in common using the resources of the network equipments.
In recent years, a new method is being widely used, in which different operators share the same network resources in order to optimize the installation, operation and maintenance costs in the network, or to minimize the Operation EXpense (OPEX) and CApital EXpenditures (CAPEX).
FIGS. 1A and 1B illustrate, respectively, a common mobile communication network in which network resources are not shared, and a common mobile communication network in which network resources are shared. In FIGS. 1A and 1B, mobile communication networks that are considered, which are used in the LTE mobile communication system, include Evolved Universal Terrestrial Radio Access Networks (eUTRANs) each comprised of evolved Node Bs (eNBs).
Specifically, FIG. 1A illustrates one eNB that is connected to a core network (or an Evolved packet core A) of one network operator (or an operator A). Therefore, the mobile communication network in FIG. 1A corresponds to a case where network resources are not shared.
FIG. 1B illustrates an example in which a core network (or an Evolved packet core A) of one network operator (or an operator A) and a core network (or an Evolved packet core B) of another network operator (or an operator B) share in common an eNB constituting an eUTRAN. This network sharing may occur in common both in a mobile communication network and a wired network.
FIGS. 2A and 2B illustrate examples of network sharing presented in the mobile communication standard such as the 3rd Generation Partnership Project (3GPP). Specifically, FIG. 2A illustrates network sharing in a Multiple Operator Core Network (MOCN), and FIG. 2B illustrates network sharing in a Gateway Core Network (GWCN).
Referring to FIG. 2A, in the MOCN, which is one of the 3GPP mobile communication standards, a core network (or an Evolved packet core A) of one network operator (or an operator A) and a core network (or an Evolved packet core B) of another network operator (or an operator B) share in common an eNB of an eUTRAN through an S1 interface.
Referring to FIG. 2B, in the GWCN, a core network (or an Evolved packet core A) of one network operator (or an operator A) and a core network (or an Evolved packet core B) of another network operator (or an operator B) share in common three Mobile Management Entities (MMEs) connected to an S1 interface, and share in common an eNB of an eUTRAN through the three MMEs.
As illustrated in FIGS. 2A and 2B, in the mobile communication standard such as 3GPP, a variety of network sharing including eUTRAN sharing are under discussion and have been implemented based on the MOCN, the GWCN and the like.
A technique for sharing resources of a radio link and a technique for sharing resources of a backhaul link, which is an upper connection link, with a relevant equipment are important in order to actually implement the network sharing technique proposed in the above mobile communication standard.
Basically, these resource sharing techniques may be equally applied not only to the wireless network, but also to existing wired network equipments such as switches, routers and the like.
The core of the technique for sharing resources of one network equipment by multiple operators is a network virtualization technique for distributing physical resources, such as network interfaces, as logical resources.
The network virtualization technique may include a Virtual Local Area Network (VLAN)-based network virtualization technique, a virtual router-based network virtualization technique, a Multi-Protocol Label Switching (MPLS)-based network virtualization technique, and the like.
The VLAN-based network virtualization technique, which is a technique that can be most easily implemented, is a technique for distributing physical network resources to a logical area that is based on a VLAN-ID for a Layer 2 (L2) packet.
The virtual router-based network virtualization technique is a technique for configuring a plurality of virtual routers by separating information of a Layer 3 (L3) routing table based on a virtual router ID, which is an ID of a virtualization area.
The MPLS-based network virtualization technique is a technique for virtualizing a network between an existing L2 header and an L3 header using a logical MPLS label. To this end, all network equipments managed by the operator need to support the complex MPLS functions.
The VLAN-based network sharing method may be most simply applied. However, it is difficult to establish network sharing over the whole network, using a VLAN which is an L2 network. Further, it is not easy to implement various additional functions including traffic engineering such as per-operator resource optimization. In addition, when network resources are operated by being linked to Internet Protocol (IP) addresses, each per-operator allocable IP address pool and a VLAN ID associated with an operator ID need to be managed by being mapped to each other.
The virtual router-based network sharing method is a method of operating virtual routers per multiple operators of each equipment. Since this method is valid only in a specific network equipment that has set up a virtual routing domain, it is difficult to transparently manage the network. In other words, when multiple equipments are operated in addition to two peers, to which a virtual router is applied, it is difficult to operate network sharing with a unified policy in the network.
The MPLS-based network sharing method is advantageous in that this method can transparently manage the network with a consistent policy in the whole network domain, based on a MPLS label-based tunneling technique, and can perform various additional functions such as fast restoration, traffic engineering and the like, provided by MPLS. However, MPLS is difficult to implement due to its high complexity, and many parts of its control plane and data plane need to be changed. In addition, in order to operate MPLS, each network equipment needs a lot of resources.
Therefore, a scenario of separating and operating the network based on MPLS to support multiple operators has many advantages, but has limitations of having high complexity and requiring a lot of resources.
In addition to the above-described network virtualization techniques, the requirements for the next-generation network additionally need to take into account priority between operators and need to provide Quality of Service (QoS) or security per flow, when multiple operators share network resources.
Moreover, multiple operators each need to operate the network using its management system, but actually it is difficult to provide this function. In addition, mobile virtual network operators need to set the network equipment through an Element Management System (EMS) of the mobile network operators.
The most serious problem is that when multiple operators share resources of one network equipment, it is very difficult to easily set the network equipment, expand the network equipment, and manage the network.
The existing network virtualization techniques basically need to set each network equipment individually. Therefore, the maintenance of each equipment is very difficult. In particular, it is difficult to apply the policy taking into account the states of many equipments managed by the network operator.
Another problem in the case where multiple operators share resources of one network equipment is the establishment of a QoS policy.
The network sharing technique basically causes competition between multiple operators, for the common resources. If congestion occurs in the network, Hierarchical QoS (H-QoS) handling related to consideration of priority between multiple operators is needed in addition to the existing QoS policy.
In other words, in the network sharing technique supporting multiple operators, processing of the hierarchical operation for multiple operators needs to be fully considered for the processing methods such as classification, marking, policing, shaping, scheduling and the like, which are the traditional QoS processing components.